1. Technical Field
The invention relates generally to semiconductor device fabrication, and more particularly, to a lateral passive device having dual annular electrodes and a related method.
2. Background Art
To optimize passive devices for radio frequency (RF) applications, the series resistance and parasitic capacitance need to be reduced. Referring to FIG. 1, one approach to reduce the capacitance is to increase a distance (Ld) between an anode 10 and a cathode 12, and minimize device area. Under this approach, conventional lateral devices, such as a PIN diode, PN diode, Schottky barrier diode (SBD), etc. are designed using striped structures. For example, as shown in FIG. 1, one stripe 10 is used as an anode and another stripe 12 is used as the cathode. A distance (Ld) is provided between stripe 10 and stripe 12. Unfortunately, to reduce resistance for this kind of structure, the device size has to be increased, which results in a device with larger layout area and a larger associated parasitic capacitance. In other words, the requirements to reduce parasitic capacitance are diametrically opposed to the requirements to reduce series resistance.